模块:Arguments

模块文档

这个文档嵌入自模块:Arguments/doc。

这个模块一般用于构建其他模块，常用语法为local getArgs = require('Module:Arguments').getArgs，此时getArgs(frame)会生成一个由模块参数组成的table。

选项

选项	说明
trim	去除参数的首尾空白字符，默认为true
removeBlanks	将空参数转换为nil，默认为true
valueFunc	用于进一步处理输入参数的Lua函数
frameOnly	只接受当前frame的参数，常见于带参数的{{#invoke:module|function|args}}
parentOnly	只接受parent frame的参数，常见于不带参数的{{#invoke:module|function}}
parentFirst	优先查找parent frame的参数，invoke可能带参数可能不带参数
wrappers	只接受来自wrappers模板（或其沙盒版本，命名形式如Template:wrappers/sandbox）的参数或当前frame的参数
readOnly	不可写入参数
noOverwrite	不可改写已有参数

注释

如本模块不能满足某些特定需要，请自行书写处理输入参数的函数。

外部链接

本页面含有来自维基百科的文本，以CC BY-SA 3.0授权引入。经过双方的修改，内容可能已与来源有很大差异。

-- This module provides easy processing of arguments passed to Scribunto from
-- #invoke. 该模块旨在为其他Lua模块所用，它不应该被#invoke直接调用。

local libraryUtil = require('libraryUtil')
local checkType = libraryUtil.checkType

local arguments = {} -- 储存最终输出


-- Generate four different tidyVal functions, so that we don't have to check the
-- options every time we call it.

local function tidyValDefault(key, val)
    if type(val) == 'string' then
        val = val:match('^%s*(.-)%s*$') -- 去除首尾的空白字符
        if val == '' then
            return nil
        else
            return val
        end
    else
        return val
    end
end

local function tidyValTrimOnly(key, val)
    if type(val) == 'string' then
        return val:match('^%s*(.-)%s*$') -- 保留空变量
    else
        return val
    end
end

local function tidyValRemoveBlanksOnly(key, val)
    if type(val) == 'string' then
        if val:find('%S') then -- 只判断变量是否仅含空字符
            return val
        else
            return nil
        end
    else
        return val
    end
end

local function tidyValNoChange(key, val)
    return val
end

local function matchesTitle(given, title)
    local tp = type( given )
    return (tp == 'string' or tp == 'number') and mw.title.new( given ).prefixedText == title
end

local translate_mt = { __index = function(t, k) return k end }

function arguments.getArgs(frame, options) -- 这个函数将包含在输出中
    checkType('getArgs', 1, frame, 'table', true)
    checkType('getArgs', 2, options, 'table', true)
    frame = frame or {}
    options = options or {}

    --[[
    -- Set up argument translation.
    --]]
    options.translate = options.translate or {}
    if getmetatable(options.translate) == nil then
        setmetatable(options.translate, translate_mt)
    end
    if options.backtranslate == nil then
        options.backtranslate = {}
        for k,v in pairs(options.translate) do
            options.backtranslate[v] = k
        end
    end
    if options.backtranslate and getmetatable(options.backtranslate) == nil then
        setmetatable(options.backtranslate, {
            __index = function(t, k)
                if options.translate[k] ~= k then
                    return nil
                else
                    return k
                end
            end
        })
    end

    --[[
    -- Get the argument tables. If we were passed a valid frame object, get the
    -- frame arguments (fargs) and the parent frame arguments (pargs), depending
    -- on the options set and on the parent frame's availability. If we weren't
    -- passed a valid frame object, we are being called from another Lua module
    -- or from the debug console, so assume that we were passed a table of args
    -- directly, and assign it to a new variable (luaArgs).
    --]]
    local fargs, pargs, luaArgs
    if type(frame.args) == 'table' and type(frame.getParent) == 'function' then
        if options.wrappers then
            --[[
            -- The wrappers option makes Module:Arguments look up arguments in
            -- either the frame argument table or the parent argument table, but
            -- not both. This means that users can use either the #invoke syntax
            -- or a wrapper template without the loss of performance associated
            -- with looking arguments up in both the frame and the parent frame.
            -- Module:Arguments will look up arguments in the parent frame
            -- if it finds the parent frame's title in options.wrapper;
            -- otherwise it will look up arguments in the frame object passed
            -- to getArgs.
            --]]
            local parent = frame:getParent()
            if not parent then
                fargs = frame.args
            else
                local title = parent:getTitle():gsub('/sandbox$', '')
                local found = false
                if matchesTitle(options.wrappers, title) then
                    found = true
                elseif type(options.wrappers) == 'table' then
                    for _,v in pairs(options.wrappers) do
                        if matchesTitle(v, title) then
                            found = true
                            break
                        end
                    end
                end

                -- We test for false specifically here so that nil (the default) acts like true.
                if found or options.frameOnly == false then
                    pargs = parent.args
                end
                if not found or options.parentOnly == false then
                    fargs = frame.args
                end
            end
        else
            -- options.wrapper isn't set, so check the other options.
            if not options.parentOnly then
                fargs = frame.args
            end
            if not options.frameOnly then
                local parent = frame:getParent()
                pargs = parent and parent.args or nil
            end
        end
        if options.parentFirst then
            fargs, pargs = pargs, fargs
        end
    else
        luaArgs = frame
    end

    -- Set the order of precedence of the argument tables. If the variables are
    -- nil, nothing will be added to the table, which is how we avoid clashes
    -- between the frame/parent args and the Lua args.
    local argTables = {fargs}
    argTables[#argTables + 1] = pargs
    argTables[#argTables + 1] = luaArgs

    --[[
    -- Generate the tidyVal function. If it has been specified by the user, we
    -- use that; if not, we choose one of four functions depending on the
    -- options chosen. This is so that we don't have to call the options table
    -- every time the function is called.
    --]]
    local tidyVal = options.valueFunc
    if tidyVal then
        if type(tidyVal) ~= 'function' then
            error(
                "bad value assigned to option 'valueFunc'"
                    .. '(function expected, got '
                    .. type(tidyVal)
                    .. ')',
                2
            )
        end
    elseif options.trim ~= false then
        if options.removeBlanks ~= false then
            tidyVal = tidyValDefault
        else
            tidyVal = tidyValTrimOnly
        end
    else
        if options.removeBlanks ~= false then
            tidyVal = tidyValRemoveBlanksOnly
        else
            tidyVal = tidyValNoChange
        end
    end

    --[[
    -- Set up the args, metaArgs and nilArgs tables. args will be the one
    -- accessed from functions, and metaArgs will hold the actual arguments. Nil
    -- arguments are memoized in nilArgs, and the metatable connects all of them
    -- together.
    --]]
    local args, metaArgs, nilArgs, metatable = {}, {}, {}, {}
    setmetatable(args, metatable)

    local function mergeArgs(tables)
        --[[
        -- Accepts multiple tables as input and merges their keys and values
        -- into one table. If a value is already present it is not overwritten;
        -- tables listed earlier have precedence. We are also memoizing nil
        -- values, which can be overwritten if they are 's' (soft).
        --]]
        for _, t in ipairs(tables) do
            for key, val in pairs(t) do
                if metaArgs[key] == nil and nilArgs[key] ~= 'h' then
                    local tidiedVal = tidyVal(key, val)
                    if tidiedVal == nil then
                        nilArgs[key] = 's'
                    else
                        metaArgs[key] = tidiedVal
                    end
                end
            end
        end
    end

    --[[
    -- Define metatable behaviour. Arguments are memoized in the metaArgs table,
    -- and are only fetched from the argument tables once. Fetching arguments
    -- from the argument tables is the most resource-intensive step in this
    -- module, so we try and avoid it where possible. For this reason, nil
    -- arguments are also memoized, in the nilArgs table. Also, we keep a record
    -- in the metatable of when pairs and ipairs have been called, so we do not
    -- run pairs and ipairs on the argument tables more than once. We also do
    -- not run ipairs on fargs and pargs if pairs has already been run, as all
    -- the arguments will already have been copied over.
    --]]

    metatable.__index = function (t, key)
        --[[
        -- Fetches an argument when the args table is indexed. First we check
        -- to see if the value is memoized, and if not we try and fetch it from
        -- the argument tables. When we check memoization, we need to check
        -- metaArgs before nilArgs, as both can be non-nil at the same time.
        -- If the argument is not present in metaArgs, we also check whether
        -- pairs has been run yet. If pairs has already been run, we return nil.
        -- This is because all the arguments will have already been copied into
        -- metaArgs by the mergeArgs function, meaning that any other arguments
        -- must be nil.
        --]]
        if type(key) == 'string' then
            key = options.translate[key]
        end
        local val = metaArgs[key]
        if val ~= nil then
            return val
        elseif metatable.donePairs or nilArgs[key] then
            return nil
        end
        for _, argTable in ipairs(argTables) do
            local argTableVal = tidyVal(key, argTable[key])
            if argTableVal ~= nil then
                metaArgs[key] = argTableVal
                return argTableVal
            end
        end
        nilArgs[key] = 'h'
        return nil
    end

    metatable.__newindex = function (t, key, val)
        -- This function is called when a module tries to add a new value to the
        -- args table, or tries to change an existing value.
        if type(key) == 'string' then
            key = options.translate[key]
        end
        if options.readOnly then
            error(
                'could not write to argument table key "'
                    .. tostring(key)
                    .. '"; the table is read-only',
                2
            )
        elseif options.noOverwrite and args[key] ~= nil then
            error(
                'could not write to argument table key "'
                    .. tostring(key)
                    .. '"; overwriting existing arguments is not permitted',
                2
            )
        elseif val == nil then
            --[[
            -- If the argument is to be overwritten with nil, we need to erase
            -- the value in metaArgs, so that __index, __pairs and __ipairs do
            -- not use a previous existing value, if present; and we also need
            -- to memoize the nil in nilArgs, so that the value isn't looked
            -- up in the argument tables if it is accessed again.
            --]]
            metaArgs[key] = nil
            nilArgs[key] = 'h'
        else
            metaArgs[key] = val
        end
    end

    local function translatenext(invariant)
        local k, v = next(invariant.t, invariant.k)
        invariant.k = k
        if k == nil then
            return nil
        elseif type(k) ~= 'string' or not options.backtranslate then
            return k, v
        else
            local backtranslate = options.backtranslate[k]
            if backtranslate == nil then
                -- Skip this one. This is a tail call, so this won't cause stack overflow
                return translatenext(invariant)
            else
                return backtranslate, v
            end
        end
    end

    metatable.__pairs = function ()
        -- Called when pairs is run on the args table.
        if not metatable.donePairs then
            mergeArgs(argTables)
            metatable.donePairs = true
        end
        return translatenext, { t = metaArgs }
    end

    local function inext(t, i)
        -- This uses our __index metamethod
        local v = t[i + 1]
        if v ~= nil then
            return i + 1, v
        end
    end

    metatable.__ipairs = function (t)
        -- Called when ipairs is run on the args table.
        return inext, t, 0
    end

    return args
end

return arguments